TWI393040B - An capacitor sensing circuit architecture of touch panel - Google Patents

Description

Capacitive sensing architecture of touch panel

The present invention relates to a capacitive touch panel, and more particularly to a capacitive sensing circuit architecture of a touch panel capable of removing low frequency noise generated by a semiconductor active device.

The capacitive touch panel has the advantages of dustproof, fireproof, scratch-resistant, strong and durable, and high resolution. However, it has the disadvantages of being expensive and easily malfunctioning due to static electricity or humidity. When the human hand is not in contact with the capacitive touch panel, the various electrodes (Electrode) are at the same potential, and the touch panel has no Electric Current. When the finger comes into contact with the touch panel, static electricity in the human body flows into the ground to generate a weak current, and the detection electrode changes according to the current value, and the contact position can be calculated. That is, by sensing the capacitance change value of each point of the touch panel, the position where the finger touches the touch panel can be obtained. Therefore, how to accurately detect the amount of change in capacitance has become the focus of touch panel development.

The detection circuit of the conventional touch panel capacitor is as shown in FIG. 1 , and the capacitor 11 to be tested is a variable capacitor, and the change in the capacitance value is due to a charged body having a capacitive effect, that is, a touch object. Or noise, etc. The capacitor-to-voltage converter 12 is used to convert the capacitance value of the capacitor 11 to be tested into a voltage value, and then amplify the signal by the amplifier 13. Finally, the low-pass filter 14 is used to mix the desired bandwidth. Filter out.

Since the operating frequency of the touch panel is low, the above conventional techniques can solve the high frequency noise, but the noise belonging to the low frequency band becomes the most important problem to be solved by the touch panel.

Please refer to FIG. 2, which is a spectrum distribution diagram of noise generated by a metal oxide semiconductor (MOS) device inside a general touch panel. There are three main types of noise generated by MOS: MOS component thermal noise, MOS component flicker noise, and Leakage Current Shot Noise. The sum of these three is the overall MOS. Total MOS Noise.

It can be clearly seen from Figure 2 that the lower the frequency, the greater the impact of Flicker Noise; conversely, when the frequency exceeds the Corener frequency ( f _c ), the effect of thermal noise is increased. In terms of the operating frequency of the touch panel, since it is a low frequency, the flicker noise will occupy most of the entire MOS noise, and the lower the frequency, the greater the impact, the touch panel signal that will work at low frequencies. The SNR (Signal to Noise Ratio) is much lower. Figure 3 is a diagram showing the noise model obtained by the noise model of Figure 2 in the circuit architecture of Figure 1. In the frequency domain, the capacitance change signal generated by the original capacitor 11 to be tested can be found. After the capacitor-to-voltage converter 12, the capacitor-to-voltage converter 12 itself generates low-frequency noise (sparkling noise is dominant). The capacitance change signal of the capacitor 11 to be tested increases the low frequency noise input, that is, V _Mod . Next, after passing through the amplifier 13, the low-frequency noise of the amplifier itself is also mixed into the signal to become V _Amp-out . Then, after passing through the low-pass filter 14, the high-frequency portion is filtered out, that is, V _out , but the low-frequency noise portion still exists, so the signal noise ratio of the low-frequency operating frequency cannot be increased, resulting in The sensitivity of the capacitive touch panel cannot be improved.

The low-frequency noise generated by the transistor component itself cannot be filtered by the conventional low-pass filter architecture, or cannot be removed by using a differential architecture, and must be removed by other means. Removal, in order to improve the signal noise ratio, and achieve the purpose of improving sensitivity.

In view of the above problems in the prior art, the present invention provides a capacitive sensing architecture for a touch panel by shifting the output frequency of the capacitor to be tested. To the high frequency working frequency band, in order to eliminate the low frequency noise, the purpose of improving the sensitivity of the capacitive sensing of the touch panel is improved.

To achieve the above objective, the present invention provides a detection circuit architecture for a capacitance of a capacitive touch panel, comprising: a waveform generator for generating a high frequency signal of a fixed voltage; a first multiplier, and the The capacitor to be tested is electrically connected and electrically connected to the waveform generator for multiplying the waveform generator by a change signal generated by the capacitor to be tested, thereby converting the operating frequency of the capacitor to be tested from the low frequency to the The high frequency band of the waveform generator constitutes a modulation signal; an amplifier is electrically connected to the first multiplier for receiving the modulation signal sent by the multiplier and amplified to an amplification signal; a multiplier, electrically connected to the waveform generator and the amplifier, for receiving the amplified signal, and reducing the high frequency band of the amplified signal to one of the original frequency bands of the change signal; and a low frequency filter, Electrically connecting with the second multiplier for receiving the amplified and restored signal and filtering the high frequency noise of the amplified and restored signal; by the above frequency conversion, the detecting circuit structure generates Frequency noise components are filtered out.

In order to achieve the frequency conversion purpose of the present invention, the present invention further provides a circuit structure of a capacitance to be tested for converting a capacitive touch panel. The method includes: a waveform generator for generating a high frequency signal of a fixed voltage; and a multiplier electrically connected to the capacitor to be tested and an amplifier, and electrically connected to the waveform generator for using the waveform generator Multiplying the signal generated by the capacitor to be tested, thereby converting the operating frequency of the capacitor to be tested from a low frequency to a high frequency band of the waveform generator, and then outputting to the amplifier.

The above and other objects, features and advantages of the present invention will become more apparent and understood.

On the touch panel, the static capacitance of each capacitor to be tested on the panel is theoretically the same. Each capacitor to be tested is considered to be a variable capacitor on the circuit, and its changed capacitance value is caused by a finger or an external touch. Since the amount of change of the capacitance to be tested is limited by the action of the human body, the operating frequency can be low frequency. On the scanning control of the touch, the capacitive sensing of each scan line must provide a fixed operating voltage to the scan line.

Due to the above basis, the present invention uses a pre-processing method to increase a high voltage in addition to the fixed operating voltage originally supplied to the capacitor to be tested. The frequency of the pulse wave voltage causes the inductive output of the capacitor to be measured to be converted into a high frequency signal. Therefore, after passing through the post-processing circuit, it will not be affected by the low-frequency noise generated by the subsequent MOS device. For the specific circuit architecture, please refer to Figure 4.

Among them, the preferred high frequency, the specification and characteristics of the visible panel. For example, a large-sized panel of more than seven inches can take an operating frequency greater than 100 kHz, the appropriate frequency, depending on the controller controllable frequency and the associated frequency generating components. For another example, a small and medium-sized panel of less than seven inches can take an operating frequency greater than 500 kHz. Similarly, the frequency selection depends on the controller controllable frequency and the associated frequency generating component.

FIG. 4 is a schematic diagram of the overall structure of the capacitance detection according to the present invention, which includes: a capacitor 110 to be tested, a first multiplier 120, a waveform generator 130, an amplifier 140, a second multiplier 150, and a low-pass filter 160. The capacitor 110 to be tested represents a variable capacitance of a scan line on the touch panel for sensing a capacitance change signal generated by a touch of a finger or other object; the waveform generator 130 provides a high frequency The voltage pulse wave is multiplied by the voltage pulse wave provided by the waveform generator 130 via the first multiplier 120, and then converted into a high voltage pulse wave. Frequency signal; amplifier 140 amplifies the high frequency signal transmitted by the first multiplier 120; then, the amplifier 140 transmits the signal to the second multiplier 150, via the reverse pulse provided by the waveform generator 130. The signal can remove the high frequency pulse of the waveform generator 130, thereby reducing the amplified change signal (low frequency signal); finally, the low pass filter 160 can filter out the high frequency noise.

The spectrum of the capacitance sensing architecture of the present invention is illustrated below in Figure 4, which illustrates how the present invention can achieve low frequency noise filtering. At the output end of the capacitor 110 to be tested, the change signal of the capacitance is in the range of the low frequency; then, at the output of the first multiplier 120, the change signal of the capacitance is multiplied by the first multiplier 120. Therefore, it is directly converted into a high-frequency voltage signal (the center frequency is f _mod ), that is, V _mod , or it can be called a modulation signal. The high frequency modulation signal at the output (V _Amp-out ) of the amplifier 140 is amplified by the amplifier 140. In addition, the low frequency noise generated by the amplifier 140 itself is also clearly seen in FIG. At this point, the frequency bands of low frequency noise and high frequency modulated signals have been distinguished. Then, all the signals are multiplied by the signal of the waveform generator 130 by the second multiplier 150 (V _Dm-out ), and as a result, the frequency band of the original high-frequency modulation signal is converted back to the low frequency, and the low frequency is The noise is converted to a high frequency band and becomes a high frequency noise. Finally, the output V _{Dm-out of the} second multiplier 150 passes through the low pass filter 160, and the output V _out filters _{out the} high frequency noise, leaving only the low frequency modulation signal and the corresponding corresponding Hot noise.

In other words, the present invention shifts the operating frequency detected by the touch panel originally belonging to the low frequency to the high frequency band by frequency shifting to avoid the frequency band in which the low frequency noise is fed into the capacitance detection. That is, the frequency domain conversion is used to achieve the low frequency noise generated by the component itself. The key point of the conversion is that when the signal is generated, the signal will be transferred to the high frequency band, and the low frequency noise generated will be avoided.

Comparing the prior art of FIG. 3 with the invention of FIG. 4, it can be found that the present invention provides a high frequency modulation signal by the waveform generator 130 and combines with the first multiplier 120 to achieve frequency conversion. . The modulation here is different from the modulation called wireless communication, which uses the modulation concept of wireless communication instead of wireless communication. In this way, the touch panel capacitive sensing signals belonging to the low frequency band can be converted to the high frequency band, thereby achieving the purpose of distinguishing from the low frequency noise generated by the internal electronic components of the amplifier 140.

Next, the second multiplier 150 and the waveform generator 130 are further transmitted. The generated high-frequency pulse wave "demodulates" the amplified modulation signal, and the amplified change signal can be restored. Finally, the high frequency signal is filtered through the low pass filter 160, which can be easily achieved by using existing techniques.

The architecture of Figure 4 illustrates the overall operation of the present invention. The main spirit of the present invention lies in the foregoing, the frequency conversion is used to convert the low frequency operating frequency of the touch panel capacitance detection to a high frequency, thereby eliminating the low frequency noise problem that occurs in the subsequent process of the signal passing through the amplifier.

In the specific circuit implementation, the architecture of the multiplier can have many different types. Two examples are listed below: Please refer to Figure 5 for a first embodiment of the multiplier architecture utilized by the present invention. The invention realizes the function of the multiplier by using two sets of electronically controlled switching switches Φ _R1 and Φ _A1 , as follows: when the waveform generator 130 is at a high potential, the electronically controlled switching switch Φ _{R1 is} short-circuited, and the electronically controlled switching The switch Φ _{A1 is} open (Open), so the waveform generator 130 charges the capacitor 110 to be measured; when the waveform generator 130 is at a low potential, the electronically controlled switch Φ _{R1 is} open (Open), and the electronically controlled switch Φ _{A1 is} shorted ( Short), then the capacitor 110 to be tested performs discharge to the amplifier 140. The electronically controlled switching switch Φ _R1 and the electronically controlled switching switch Φ _A1 are synchronized with the frequency of the waveform generator 130. Therefore, if the capacitance value of the capacitor 110 to be tested changes in the capacitance value during the charging and discharging process, the capacitance will occur. The change can be detected by the end of the amplifier 140.

Please refer to FIG. 6, which illustrates a second embodiment of the multiplier architecture utilized in the present invention, which is used in an example of a differential capacitance sensing architecture. The differential capacitance detection architecture is a technique for detecting the difference in capacitance between two scanning lines to perform touch determination. Therefore, the differential capacitance detecting architecture has two capacitors to be tested, as shown in FIG. 6, which are respectively the capacitor 111 to be tested and the capacitor 112 to be tested, and the capacitance values thereof are C1 and C2, respectively. Similarly, the waveform generator 130 is used in the architecture, and the electrical control switch 111 and the capacitor to be tested 112 are respectively designed with an electronically controlled switching switch Φ _R1 and an electronically controlled switching switch Φ _A1 , an electronically controlled switching switch Φ _R2 and an electronically controlled switching Switch Φ _A2 . The two sets of electronically controlled switching switches respectively control the open circuit and the open circuit of the capacitor 111 to be tested and the capacitor 112 to be tested and the waveform generator 130 and the amplifier 140, so that the capacitor 111 to be tested and the capacitor 112 to be tested form an amplifier 140. High frequency input signal. The manner of switching is as described in FIG. 5, and details are not described herein again.

Then, the capacitor 111 to be tested and the capacitor 112 to be tested are respectively input to the two ends of the input of the amplifier 140 to form a differential structure. The subsequent circuit can determine the difference between the capacitance values of the capacitor 111 to be tested and the capacitor 112 to be tested. Different, you can determine which scan line is touched.

Figure 5 illustrates the multiplier implementation architecture of a general capacitive touch panel, and Figure 6 illustrates the multiplier implementation architecture of a differential capacitive touch panel. It is illustrated that the present invention can be applied to different capacitive touch panel determination methods, and the same can be achieved for converting the low frequency operating frequency to the high frequency operating frequency. As long as the low frequency operating frequency can be converted to the high frequency operating frequency in the simplest manner, the purpose of the low frequency noise avoidance desired by the present invention can be achieved.

The embodiments of Figures 5 and 6 illustrate only one example of a multiplier. In fact, those skilled in the art will be able to devise various multipliers in accordance with the teachings of the present invention to achieve the object of the invention. Therefore, the following description will not repeat other multiplier architectures.

Next, a simple implementation circuit using the present invention on an amplifier will be described. Through the following embodiments, it can be seen that the embodiments of Figs. 5 and 6 can obtain a high frequency switching voltage at the output of the amplifier 140.

Please refer to FIG. 7 , which is a circuit diagram of an amplifier used in a general capacitive touch panel of the present invention. Comparing Fig. 5, it can be seen that the seventh figure is to add the bypass capacitor C3 to the circuit structure of the amplifier diagram at the end of the amplifier 140, and to be connected in parallel with an electronically controlled switch Φ _R3 ; meanwhile, at the output of the amplifier 140 Add an electronically controlled switch Φ _{A3 to the end} . Among them, the electronically controlled switching switch Φ _R3 is synchronized with the electronically controlled switching switch Φ _R1 , and the electronically controlled switching switch Φ _A3 is synchronized with the electronically controlled switching switch Φ _A1 .

In the first stage, the electronically controlled switching switch Φ _{R1 is} short-circuited with the electronically controlled switching switch Φ _R3 , and the electronically controlled switching switch Φ _A1 and the electronically controlled switching switch Φ _{A3 are} open, and the power of the capacitor 130 to be tested is Q1=C ₁ xV _mod , and the capacitance The power of C ₃ is Q3=0. Then, in the second stage, the electronically controlled switching switch Φ _R1 and the electronically controlled switching switch Φ _{R3 are} open, and when the electronically controlled switching switch Φ _{A1 is} short-circuited with the electronically controlled switching switch Φ _A3 , the output terminal of the amplifier 140 generates an output voltage of V _o . Therefore, the total amount of electricity of the capacitor 130 to be tested and the capacitance C ₃ is: Q = Q1 + Q3 = C ₁ V + C ₃ (VV _o ) = (C ₁ + C ₃ ) VC ₃ V _o

Where: V _o =A(V _agnd -VV _os ), A is the amplification factor of the amplifier, V _mod is the reference voltage provided by the waveform generator 130, V is the voltage of the terminal 110 of the capacitor to be tested, and V _o is the output end of the amplifier 140 Voltage.

Thus, V = V _agnd - V _os - V _o / A. In the first phase of switching, the stored power is Q1, and the second phase is Q. Q1=Q, then: C _{1 xV rgf} =(C ₁ +C ₃ )(V _agnd -V _os -V _o /A)-C ₃ V _o ≒(C ₁ +C ₃ )(V _agnd -V _os ) -C ₃ V _o

V _o =-C ₁ /C ₃ (V _mod -V _agnd )+V _agnd -(1+C ₁ /C ₃ )V _os

That is, the signal V _o output terminal of the amplifier 140 consists of three components, V _mod, V _agnd with V _os. Therefore, when the capacitance to be tested 110 belonging to the variable capacitor changes in capacitance value, that is, the value of C ₁ changes, V _o also changes accordingly. Among them, V _mod is a high frequency pulse wave. Therefore, the capacitance change of the capacitor 110 to be tested can be detected at the output end thereof through the amplification of the amplifier 140, and the AC change can also be detected. Subsequent processing is as described in FIG. 4, and details are not described herein again.

Next, please refer to FIG. 8 , which is a circuit diagram of an amplifier used in a differential capacitive touch panel of the present invention. Comparing Figure 6, it can be seen that Figure 8 shows that the circuit structure of Figure 6 adds two sets of bypass capacitors and electronically controlled switches at the amplifier 140 end, respectively: bypass capacitor C ₃ and an electronically controlled switch Φ _R3 is connected in parallel, and an electronically controlled switching switch Φ _A3 is added at the output end of the amplifier 140, which is matched with the detection of the capacitor 111 to be tested; the bypass capacitor C _{4 is} switched with an electronically controlled switch Φ _R4 and In parallel, an electronically controlled switching switch Φ _A4 is added to the output of the amplifier 140, which is matched with the detection of the capacitor 112 to be tested. Among them, the electronically controlled switch Φ _R3 , the electronically controlled switch Φ _R4 is synchronized with the electronically controlled switch Φ _R1 , the electronically controlled switch Φ _R2 , and the electronically controlled switch Φ _A3 , the control switch Φ _A4 and the electronically controlled switch The switch Φ _A1 and the electronically controlled switch Φ _{A2 are} synchronized.

The first stage, electronically controlled switch Φ _R1 , electronically controlled switch Φ _R2 , electronically controlled switch Φ _R3 and electronically controlled switch Φ _R4 short circuit, and electronically controlled switch Φ _A1 , electronically controlled switch Φ _A2 , electronic control The switch Φ _A3 and the control switch Φ _{A4 are} open circuit, the electric quantity of the capacitor 111 to be tested is Q1=C ₁ xV _mod , and the electric quantity of the capacitor C ₃ is Q3=0; the electric quantity of the capacitor 112 to be tested is Q2=C ₂ xV _mod , and the capacitance The power of C ₄ is Q4=0. Then, in the second stage, the electronically controlled switching switch Φ _R1 , the electronically controlled switching switch Φ _R2 , the electronically controlled switching switch Φ _{R3 ,} and the electronically controlled switching switch Φ _R4 open circuit, and the electronically controlled switching switch Φ _A1 , the electronically controlled switching switch Φ _A2 The electronically controlled switching switch Φ _A3 is short-circuited with the control switching switch Φ _A4 , and the output terminal of the amplifier 140 generates an output voltage of V _o . After calculation, it can be obtained: V _o =-(C ₁ -C ₂ )/(C ₃ +(C ₁ +C ₂ /2))(V _mod -V _agnd )+kV _os

Where k = (1 + C ₁ / C ₃ ) (C ₂ + C ₃ ) / (C ₃ + (C ₁ + C ₂ )/2)

Similarly, the signal V _o output terminal of the amplifier 140 consists of three components, V _mod, V _agnd with V _os. Therefore, when the capacitance to be tested 111 or the capacitance to be tested 112 which is a variable capacitor changes in capacitance value, that is, the value of C ₁ or C ₂ changes, V _o also changes accordingly. Among them, V _mod is a high frequency pulse wave. Therefore, the capacitance change of the capacitor 110 to be tested can be detected at the output end thereof through the amplification of the amplifier 140, and the AC change can also be detected. Subsequent processing is as described in FIG. 4, and details are not described herein again.

In the above description, the design of the amplifier end can be very diverse, and the object to be achieved by the present invention can be achieved, and other examples are not further described herein.

Further, the waveform generator disclosed in the present invention uses a high-frequency pulse wave as an embodiment. Pulse waves are a preferred embodiment of the invention as they are relatively easy to implement in digital circuits. However, in addition to the pulse wave, other waveforms such as a sine wave, a sawtooth wave, etc., may be used, the purpose of which is to provide a high frequency signal to the capacitor to be tested, and to enable the conversion of its low frequency operating frequency to a high frequency tone. Change signal.

While the preferred embodiment of the invention has been described above, it is not intended to limit the invention, and it is obvious to those skilled in the art that the invention may be modified and modified without departing from the spirit and scope of the invention. The patent protection scope of the invention is subject to the definition of the scope of the patent application attached to the specification.

11‧‧‧Measured capacitance

12‧‧‧Capacitor-to-voltage conversion circuit

13‧‧‧Amplifier

14‧‧‧Low-pass filter

110‧‧‧Measured capacitance

120‧‧‧First multiplier

C ₂ ‧‧‧ capacitor

C ₃ ‧‧‧ capacitor

C ₄ ‧‧‧ capacitor

Φ _A1 ‧‧‧Electric control switch

111‧‧‧Measured capacitance

112‧‧‧Measured capacitance

130‧‧‧ Waveform Generator

140‧‧‧Amplifier

150‧‧‧Second multiplier

160‧‧‧Low-pass filter

C ₁ ‧‧‧ capacitor

Φ _A2 ‧‧‧Electric control switch

Φ _A3 ‧‧‧Electric control switch

Φ _A4 ‧‧‧Electric control switch

Φ _R1 ‧‧‧Electric control switch

Φ _R2 ‧‧‧Electric control switch

Φ _R3 ‧‧‧Electric control switch

Φ _R4 ‧‧‧Electric control switch

Figure 1 is a conventional touch panel capacitance detection circuit; Figure 2 is a spectrum distribution diagram of noise generated by a metal oxide semiconductor (MOS) element inside the touch panel; Figure 3 is the second picture The noise model of the figure is set with the noise model obtained in the circuit structure of FIG. 1; the fourth figure is the overall structure diagram of the capacitance detection of the present invention; and the fifth figure is the first of the multiplier architecture used in the present invention. Embodiment 6 is a second embodiment of a multiplier architecture used in the present invention; FIG. 7 is a circuit architecture of an amplifier applied to a general capacitive touch panel of the present invention; and FIG. 8 is a present invention The circuit architecture of an amplifier used in a differential capacitive touch panel.

110‧‧‧Measured capacitance

120‧‧‧First multiplier

130‧‧‧ Waveform Generator

140‧‧‧Amplifier

150‧‧‧Second multiplier

160‧‧‧Low-pass filter

Claims (11)

A detection circuit structure for a capacitive touch panel to be tested, comprising: a waveform generator for generating a fixed voltage high frequency signal; a first multiplier electrically connected to the capacitance to be tested, and the The waveform generator is electrically connected to multiply the waveform generator by a change signal generated by the capacitor to be tested, thereby converting the operating frequency of the capacitor to be tested from a low frequency to a high frequency band of the waveform generator, thereby forming a modulation signal; an amplifier electrically coupled to the first multiplier for receiving the modulation signal sent by the multiplier and amplified to an amplification signal; a second multiplier, and the waveform generator and The amplifier is electrically connected to receive the amplified signal, and restores the high frequency band of the amplified signal to one of the original frequency bands of the change signal; and a low frequency filter electrically connected to the second multiplier The high frequency noise of the amplified and restored signal is received by the amplified and restored signal; and the low frequency component noise generated by the detecting circuit structure is filtered out by the above frequency conversion. For example, in the detection circuit structure of the capacitive touch panel to be tested, the first multiplier is composed of two sets of electronically controlled switches. The first electronically controlled switch is formed to switch the connection between the waveform generator and the capacitor to be tested; and the second electronically controlled switch is formed to form a connection switch between the capacitor to be tested and the amplifier; wherein The first electronically controlled switch and the second electronically controlled switch-on relationship are synchronized with the waveform generator, and an Open (Short) action is performed according to the waveform provided by the waveform generator. The detection circuit structure of the capacitive touch panel to be tested is the second aspect of the invention, wherein the amplifier includes a bypass capacitor and a third electronically controlled switch, which are formed at the input end of the amplifier. And an output terminal, and a fourth electronically controlled switch, which is formed at an output end of the amplifier and an input end of the second multiplier; the third electronically controlled switch-on relationship and the fourth electronically controlled switch-on relationship and the waveform The generator synchronizes and performs an Open-Short action according to the waveform provided by the waveform generator. For example, in the detection circuit structure of the capacitive touch panel to be tested, the capacitive touch panel adopts a differential capacitance detection architecture, which simultaneously detects two capacitances to be tested. Obtain a differential signal The first multiplier comprises a third multiplier and a fourth multiplier, and each of the two multipliers is composed of two sets of electronically controlled switches, respectively: a first electronically controlled switch, forming the waveform generation Switching connection between the device and the capacitor to be tested; and a second electronically controlled switch to form a connection switch between the capacitor to be tested and the amplifier; wherein the first electronically controlled switchover is related to the second electronically controlled switch-on relationship The waveform generator is synchronized, and an Open (Short) action is performed according to the waveform provided by the waveform generator. For example, the detection circuit structure of the capacitive touch panel to be tested is disclosed in claim 4, wherein the amplifier includes a first bypass capacitor connected in parallel and a third electronically controlled switch, which is formed in the amplifier. a first input end and a first output end, and a fourth electronically controlled switch switch formed at the first output end of the amplifier and the input end of the second multiplier; and the amplifier has a second bypass capacitor connected in parallel And a fifth electronically controlled switch, which is formed on the second input end and the second output end of the amplifier, and a sixth electronically controlled switch, which is formed on the second output end of the amplifier and the second multiplication The input end of the device; the third electronically controlled switch, the fourth electronically controlled switch, the fifth electronically controlled switch, and the sixth electronically controlled switch-on relationship and the waveform The generator synchronizes and performs an Open-Short action according to the waveform provided by the waveform generator. For example, in the detecting circuit structure of the capacitive touch panel to be tested, the high frequency signal generated by the waveform generator is determined by the panel type, for example, a panel larger than seven inches. The operating frequency greater than 100 kHz can be used to control the control frequency of the touch panel and the associated frequency generating component is determined; for example, a small and medium size panel of less than seven inches can take an operating frequency greater than 500 kHz to control the The control frequency of the touch panel and the associated frequency generating components are preferably determined. The detection circuit structure of the capacitance of the capacitive touch panel to be tested according to any one of claims 1 to 6, wherein the waveform generator generates one of a pulse wave, a sine wave and a triangular wave. A circuit structure for converting a capacitive touch panel to be tested, comprising: a waveform generator for generating a fixed voltage high frequency signal; and a multiplier electrically connected to the capacitor to be tested and an amplifier, and The waveform generator is electrically connected to multiply the waveform generator by a signal generated by the capacitor to be tested, thereby rotating the operating frequency of the capacitor to be tested from a low frequency Switching to the high frequency band of the waveform generator, and then outputting to the amplifier; wherein the multiplier is composed of two sets of electronically controlled switching switches, respectively: a first electronically controlled switching switch, forming the waveform generator and the Switching connection of the capacitor to be tested; and a second electronically controlled switch to form a connection switch between the capacitor to be tested and the amplifier; wherein the first electronically controlled switch is switched to the second electronically controlled relationship with the waveform generator Synchronization, according to the waveform provided by the waveform generator, performs an Open-Short action. A circuit structure for converting a capacitive touch panel to be tested, comprising: a waveform generator for generating a fixed voltage high frequency signal; and a multiplier electrically connected to the capacitor to be tested and an amplifier, and The waveform generator is electrically connected to multiply the waveform generator by a signal generated by the capacitor to be tested, thereby converting the operating frequency of the capacitor to be tested from a low frequency to a high frequency band of the waveform generator, and then outputting to The amplifier; wherein the capacitive touch panel adopts a differential capacitance detecting architecture, which simultaneously detects two capacitors to be tested to obtain a differential signal to determine In the method of touching, the multiplier comprises a first multiplier and a second multiplier, and each of the two electronically controlled switching switches is formed by: a first electronically controlled switching switch, forming the waveform generator and the waiting The connection of the measurement capacitor is switched; and the second electronically controlled switch is formed to switch the connection between the capacitor to be tested and the amplifier; wherein the first electronically controlled switch and the second electronically controlled switch-on relationship are synchronized with the waveform generator According to the waveform provided by the waveform generator, an open (Short) action is performed. For example, in the detecting circuit structure of the capacitive touch panel to be tested, the high frequency signal generated by the waveform generator is determined by the panel type, for example, a panel larger than seven inches. The operating frequency greater than 100 kHz can be used to control the control frequency of the touch panel and the associated frequency generating component is determined; for example, a small and medium size panel of less than seven inches can adopt an operating frequency greater than 1 MHz to control the The control frequency of the touch panel and the associated frequency generating components are preferably determined. The detection circuit structure of the capacitance of the capacitive touch panel to be tested according to any one of claims 8 to 10, wherein the waveform generator generates a pulse Wave, sine wave, triangle wave, one of them.